Dual-Channel (Video) Encoding

If you have an E2211, E2221, or E4300 encoder, you have the ability to take advantage of dual-channel encoding (i.e. encoding from two separate video sources at the same time). A dual-channel encoder allows you to broadcast two synchronized video channels simultaneously.  A setup like this can allow you to, for example, stream both a lock-down head-to-toe video shot and IMAG (image magnification/close-up) video shot simultaneously, providing an immersive feel at the remote venue - as if the audience were in the same room as the live performer.

To stream simultaneous video feeds at 1080p with 60 frames per second, make sure your settings in Studio and on your decoder have been properly configured to receive both videos.

Set Up a Dual-Channel Encoder Event for Multi-Site

To take advantage of this feature, you will need at least two cameras with a constant video feed. You can simultaneously broadcast two feeds at any given time. 

In order for audio to be captured, all your audio channels must be embedded into the SDI or HDMI signal that's routed to the encoder's first video input card.

1. Create a dual-channel encoder preset

Before you can run an event using both video channels on your encoder, make sure you have a dual-channel encoder preset ready to use with your event.

1. In Studio, navigate to Settings > Encoder Presets.
2. Click + Add Encoder Preset.
3. In the Video Channels dropdown, select 2 video channels.
4. Select the H264 or HEVC codec. For guidance on which codec may be best for your event, contact Resi Support.
5. Configure the rest of your preset details. Learn more
6. Click Save.

2. Create an Event

Next, schedule an event. You can do this either by creating a schedule or by starting an event manually (Learn more). Remember that you should have your recording equipment plugged into your encoder and transmitting a signal before you turn on the encoder. Proceed by doing one of the following.

2a. Schedule an event

1. 1. Navigate to the Schedule in Studio.
   2. Click +Add Event.
   3. Configure your event (Learn more). Make sure the following options are selected:
      • Encoder Preset: select the encoder preset with your dual-channel settings.
      • Encoder Channel: select the encoder channel that is associated with the decoder and venue you would like to send your broadcast. (Learn more)
   4. When you are done, click Save.

2b. Manually start an event

1. Navigate to Settings > Encoders in Studio.
2. Click Start next to your encoder.
3. In the modal that appears, configure the following settings: 
   • Encoder Preset: select the encoder preset with your dual-channel settings.
   • Encoder Channel: select the encoder channel that is associated with the decoder and venue you would like to broadcast to. (Learn more)
4. Click the Start Encoder button.
5. Do one or both of the following, depending on whether you would like to start a multisite event, web event, or both:
   • Log into your decoder and access the encoder channel you are encoding video footage to. (Learn more)
   • Navigate to the Library > Encoder Videos page in Studio and start a web event from there. (Learn more)

3. Configure your outputs

Next, make sure your physical connections and decoder settings are correct before your event runs.

1. Look for the 1 and 2 below each output on the back of your decoder.
2. Plug your output cables into the back of your decoder. When you plug the other end of your cables into your screen or projector, make sure the video channel you want corresponds to the correct display (i.e. 1 on the back of your decoder corresponds to channel 1, etc.).
3. Log into your decoder.
4. Navigate to Settings > Audio & Video output.
5. In the Output Format area, click on the Output Device drop-down.
6. Select the Both 1 & 2 option.
7. When you are finished, navigate back to the Events tab.
8. When it’s time for you to start loading your event, click the refresh button and select your scheduled event when it shows.

You should see two different video feeds displayed in your decoder interface. The one on the left is video channel 1 and the one on the right is video channel 2.

Broadcast Unique Video Feeds to Different Destinations

Now that you can access your dual-channel videos from a decoder at a multi-site venue, configure your event to broadcast unique video feeds to independent online destinations (e.g. a regular broadcast featuring the main video feed and another for an ASL broadcast from a second camera that has the translator featured prominently in the shot).

Keep in mind when sending a unique video feed to two different destinations: 

• Since all of the video data (i.e. data from both video channels) is sent to each destination, this can result in large amounts of bandwidth usage. 
• In addition, channels must be individually re-transcoded when sent to web or social media, which may result in slightly lower quality. 

For more information, read our article on Video Compression.

1. Create web preset(s)

Before you can select a destination for your web event, create a web preset configured with which video channel you want to use. The way you set it up depends on how you’re broadcasting content. (i.e. whether you intend on broadcasting to two different web/social media destinations, or you will send one feed to web/social media, and another to a multisite venue).

1. Navigate to Settings > Web Presets.
2. Click + Add Web Preset.
3. Click the Encoder Video Channel drop-down.
4. If you want your web destinations to receive the content that goes through video channel 1, select Ch1. Otherwise, select Ch2.
5. Choose a name for the web preset, and configure the audio channels.
6. Click Save.

If you are broadcasting to two unique web or social media destinations, repeat these steps, and in step 4 select Ch2 this time. 

2. Manually start or schedule an event

After you have created a web preset that works for your broadcast, you can proceed with either manually starting or scheduling your event:

2a. Manually start an event

1. Navigate to Settings > Encoders in Studio.
2. Click Start next to your encoder.
3. In the modal that appears, configure the following settings: 
   • Encoder Preset: select the encoder preset with your dual-channel settings.
   • Encoder Channel: select the encoder channel that is associated with the decoder and venue you would like to broadcast to. (Learn more)
4. Click the Start Encoder button.
5. Do one or both of the following, depending on whether you would like to start a multisite event, web event, or both:
   • Log into your decoder and access the encoder channel you are encoding video footage to. (Learn more)
   • Navigate to the Library > Encoder Videos page and start a web event from there. (Learn more)

2b. Schedule an event

1. Navigate to the Schedule in Studio.
2. Click the +Add Event button.
3. Configure your event (Learn more). When you do this make sure the following options are selected:
   • Encoder Preset: select the encoder preset with your dual-channel settings.
   • Encoder Channel: select the encoder channel that is associated with the decoder and venue you would like to broadcast to. (Learn more)
4. Click the +Add Destination button.
5. Do one of the following depending on your setup:
   • If you have two unique web broadcasts, choose which will be your primary destination, select the web preset you created with Ch1. 
   • If you have a web and multisite broadcast, select the web preset you created with Ch2.
6. When you are done, click Save.
7. Proceed by doing one of the following:
   • For two web broadcasts, go through these steps again for your secondary channel, with the exception of making sure your web preset for your secondary destination is set to Ch2.
   • For a web and multisite broadcast, check the back of your decoder to make sure your display is plugged into the channel 1 video card and log into it to ensure that your Output Device drop-down, under the Audio & Video settings in the decoder interface, is set to 1 Only.

Adjust Your Channel 2 Video Offset

We strongly recommend testing any dual-channel encoder event before going live. We also recommend adjusting the video offset for your 2nd video channel in case you notice a delay between your audio and channel 2 video feed. Since all of your audio is routed through the first encoder channel, you can use this as a baseline. You can then adjust the channel 2 offset in your encoder preset.

1. Test your broadcast by following the steps above and creating a test event, then go live.
2. Monitor your event from your decoder and/or private stream on web or social media.
3. If you notice any delay between your video channels, try to get a rough estimate of how much delay there is (e.g. if you count 3 seconds between when a presenter’s lips move and when you hear them speak, you will have an offset value of 3).
4. Stop the event.
5. Navigate to Settings > Encoder Presets.
6. Click the encoder preset you want to edit.
7. Adjust the Channel 2 Offset setting with the slider or counter:
   • If channel 2 video feed runs ahead of the audio, adjust the offset to the positive value for the (e.g. 3).
   • If the channel 2 video runs behind the audio, adjust the offset to the negative value (e.g. -3).
8. Click Save.
9. Test your broadcast again to make sure the delay has been correctly set.

While you can configure the delay for two feeds in Studio, to delay audio, you need to use an audio delay device and configure it at either the encoding or decoding site.